Rotary electric switch with improved internal actuating and contact structure including tolerance compensator means



M h 8. 1967 K. c. ALLISON ETAL' 18 ROTARY ELECTRIC SWITCH WITH IMPROVEDINTERNAL ACTUATING AND CONTACT STRUCTURE INCLUDING TOLERANCE COMPENSATORMEANS Filed April 14, 1965 2 Sheets-Sheet l /a =FIGURE 2.

39 //w INVENTORS 3 KENNETH C. ALLISON THOMAS R. BEAVER BY AT ORNEY March28. 1967 K. c. ALLISON ETAL ,3 v

ROTARY ELECTRIC SWITCH WITH IMPROVED INTERNAL ACTUATING AND CONTACTSTRUCTURE INCLUDING TOLERANCE COMPENSATOR MEANS Filed April 14, 1965 2Sheets-Sheet 2 FIGURE 3 FIGR 5 INVENTORS KENNETH C. ALLISON THOMAS R.BEAVER United States Patent 3,311,718 ROTARY ELECTRIC SWITCH WITH IM-PROVED INTERNAL ACTUATING AND CONTACT STRUCTURE INCLUDDIG TOLERANCECOMPENSATOR MEANS Kenneth C. Allison, Crystal Lake, 11]., and Thomas R.Beaver, Elkhart, Ind, assignors to CTS Corporation, Ellrhart, lnd., acorporation of Indiana Filed Apr. 14, 1965, Ser. No. 464,255 16 Claims.(Cl..20ll11) The present invention relates to switches, and, moreparticularly, to a miniature rotary electric switch.

In order to obtain accurate operation and wiping action between amovable contactor and a plurality of stationary contacts as the size ofthe parts of a switch decreases, it is necessary to maintain the partsto closer than standard tolerances. Manufacturing such parts to closerthan standard tolerances, however, increases the cost of the switchconsiderably. It would, therefore, be desirable to provide an improvedminiature rotary electric switch with parts having standardmanufacturing tolerances and employing a tolerance compensator forcounteracting variations resulting from the tolerances.

As the size of a switch decreases, the switch is more difiicult todesign, especially the design of the movable contactor engageable withthe stationary contacts. Genintegral with a spring arm but, as thelength of a spring arm decreases, the ability to maintain a definedcontact pressure over a predetermined distance decreases. It would,therefore, also be desirable to provide a miniature electric switch witha movable spring eontactor employing a torsion bar for maintaininguniform contact pressure.

Another ditficulty with miniaturization of electrical switches of therotatable type is to provide adequate strength in a stop assembly forhalting rotation of the switch when desired without shearing the shaftor a part of the stop assembly. Generally when a stop arm engages afixed stop or shoulder in the housing for halting rotation, thedimension of the stop arm and the shoulder as well as the shaft aredecreased as the size of the switch is decreased. It would, therefore,be desirable to decrease the overall size of the stop assembly withoutdecreasing the stop strength thereof.

Accordingly, it is an object of the present invention to provide animproved miniature rotary electric switch with a tolerance compensator.

Another object of the present invention is to provide a miniature rotaryelectric switch with a torsion bar spring contactor.

An additional object of the present invention is to provide a miniaturerotary electric switch with improved stop strength.

A further object of the present invention is to provide a miniaturerotary electric switch with a detent mechanism having a U-shaped detentcage fixedly secured to a shaft and a stop integral with the cage.

Another object of the present invention is to provide a miniature rotaryelectric switch adapted for single-pole or multi-pole operation.

Still an additional object of the present invention is to provide aminiature rotary electric switch with a housing having axial and radialbearings for supporting a shaft axially and radially.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds, and the features ofnovelty characterizing the invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

Briefly, the present invention is concerned with an improved miniaturerotary electric switch comprising a cupshaped housing defining a chamberopen at one end. A

Patented Mar. 28, 1967 contact carrier supporting a plurality ofstationary contacts closes the one end of the chamber. Axial and radialbearing surfaces are provided in the housing for rotatably supporting ashaft. A torsion bar spring contactor for wiping engagement with thestationary contacts is carried by a driver constrained to rotate withthe shaft. Interposed between the detent mechanism and the driver andoperably coupling the detent mechanism to the driver is a tolerancecompensator biasing the shaft outwardly of the housing and the driveragainst the contact car-rier, thereby counteracting variations due totolerances and enabling the switch to be constructed from partscontaining standard manufacturing tolerances. The torsion bar springcontactor is provided with a pair of contact arms extending fromdiametrically opposite ends of a torsion bar to provide adequate springpressure during operation of the switch. Indexing of the switch isobtained with a detent mechanism fixedly secured to the end of the shaftand a stop arm integral with the detent mechanism limits rotation of theshaft.

For a better understanding of the present invention, reference may behad to the accompanying drawings wherein the same reference numeralshave been applied to like parts and wherein:

FIGURE 1 is an enlarged isometric view of a miniature rotary electricswitch;

FIGURE 2 is a sectional view taken along line II-II of the svw'tch shownin FIGURE 1;

FIGURE 3 is an exploded view of the switch shown in FIGURE 1;

FIGURE 4 is a sectional view of a torsion bar spring contactor shown inFIGURES 2 and 3 of the drawings; and

FIGURE 5 is a top view of an index sleeve best shown in FIGURE 3 of thedrawings.

Referring now to the drawings and, more particularly, to FIGURES 2 and 3thereof, there is illustrated a miniature rotary electric switch 10comprising a cup-shaped housing 11 defining a chamber 12 having anopening 13 at one end thereof, a contact carrier 20 closing the open endof the chamber, a detent assembly 30 mounted in the housing for indexinga spring contactor 50 for wiping engagement with a plurality ofstationary contacts 22 and a tolerance compensator 40.

Considering first the housing 11 it is provided with a forwardlyprojecting threaded bushing 15 for securing the housing to a not-shownmounting panel or the like with a nut. A pair of flat surfaces 15a onthe bushing'assures proper alignment of the switch in the mountingpanel. Concentric with the bushing 15 at the front end of the housing isan annular groove 16 containing an O-ring 17 for sealing the housing tothe mounting panel. The cylindrical portion 11a of the housing adjacentto the open end thereof is provided with an inwardly extendingprojection 18 located in a slot 21 in the periphery of the contactcarrier 20 and properly aligning the contact carrier at the open end ofthe housing. The peripheral edge 11b of the housing is rolled over asshown in FIGURES 1 and 2 of the drawings to secure the contact carrierto the housing. A shoulder 19 prevents inward movement of the contactcarrier 20. A plurality of circumferentially spaced stationary contacts22 are generally insert molded or inserted into slots provided in thecontact carrier 20 and then staked to secure the stationary contacts 22to the contact carrier. To seal the contact carrier to the housing, alayer of epoxy 23 or suitable insulating material is applied to theouter surface of the contact carrier.

The threaded bushing 15 is provided with a bore 15b rotatably supportinga shaft 24- extending into the sealing portion 12:: of the chamber 12.Sealing the exterior front end of the housing '11 from the chamber 12 iseffected with another O-ring 25 compressed between the shaft andcylindrical wall of the sealing portion 12a as best shown in FIGURE '2of the drawings. A pair of peripheral shoulders 26 integral with theshaft prevent movement of the O-ring 25 on the shaft 24. Preferably thebearing face 26a of the outer peripheral shoulder 26 engages the upperwall or bearing surface 12b of the sealing section providing a shaftbearing normal to the bearing between the shaft and the bore 15b, theformer being referred to as a radial bearing and the latter beingreferred to as an axial bearing.

In accord with the present invention, indexing of the switch 10 iseffected with the detent assembly 30 fixedly secured to the shaft 24-extending in the chamber 12.

More specifically, the detent assembly comprises a rotatable U-shapedcage 31 having an elongated slot 31a (see FIGURE 2) in the bight portionthereof, and a wide tongue 24a integral with the end of the shaft 241-fits into the elongated slot 31a. The shaft 24 is fixedly secured to thecage 31 by staking the tongue. A detent or index sleeve 32. as bestshown in FIGURES 3 and of the drawings is disposed in the front portionof the chamber 12 around the cage 31 and rearward movement of the sleeveis prevented by shoulders formed by inward depressions 11c. A dimple 33in the wall of the housing 1'1 forming an inwardly extending projectionin the chamber wall and located in a slot 32a provided in the rim of theindex sleeve 32 properly aligns the sleeve in the housing. The indexsleeve is provided with a plurality of spaced downwardly extendingcurved fingers 32b. A pair of detent balls 34, each ball being greaterin diameter than the distance between adjacent fingers, are biasedagainst the index sleeve by a coiled helical spring 35 disposed in theU-shaped cage 31. Each of the balls 34 assumes a stable position whendisposed in a space between adjacent. fingers. The number of detentpositions of the switch is altered by changing the number of curvedfingers 32b on the index sleeve 32 and the number of stationary contacts22.

Preferably and as best illustrated in FIGURE 5 of the drawings, theindex sleeve 32 is provided with an inwardly extending arcuate stopmember 36 engageable by an upwardly extending stop arm 37 of therotatable U-shaped cage 31 for halting rotation of the shaft. The angleof rotation of the shaft is limited to the angle defined by the removedportion of the arcuate stop member.

As will become apparent from the following description, a driver 39 isoperably coupled to the U-shaped cage 31 by means of a tolerancecompensator 40. Considering first the driver 39, it is preferablycup-shaped and of molded construction having an elongated groove 39aextending across and intersecting a pair of spaced transverse grooves 3%receiving the spring contactors 50 to provide a two-pole switch. Thenumber of poles of the switch is altered by changing the number ofspring contactorsStl, e.g., one spring contactor 50 is employed when asingle-pole switch is desired. Each of the spring contactors 50comprises an elongated torsion bar 51 lying in the transverse slots 3%.Dimples 51a on each end of the torsion bar 51 provide a two pointsupport. Extending outwardly from diametrically opposite ends of thetorsion bars are a pair of contact arms 52 having a connecting portion52a extending substantially normal to the torsion bar, and a contactcarrying portion 52b extending in spaced parallel relationship to thetorsion bar and carrying a contact button 520. Preferably each of thecontact buttons 520 is disposed in a plane bisecting the torsion bartransversely, and the contact arm is preformed at an angle to the majorplane of the torsion bar. Forming a small angle in the torsion bar 51 asshown in FIGURE 5 of the drawings assures that a space is maintainedbetween the center of the torsion bar and the bottom wall of the slot 3%to facilitate twisting of the torsion bar as the spring contactor 50 iswiped on the contacts 22. The contact button adjacent to the center ofthe driver engages a stationary center contact 22a while the othercontact button adjacent to the cylindrical wall 39c of the driver 39engages the circumferentially spaced stationary contacts as the driveris rotated.

Securing of the tolerance compensator 40 to the U- shaped cage 31 isperformed by suitable means such as staking a plurality of ears 31blocated in the openings 40a of the tolerance compensator 40. The driver39 is also provided with a pair of apertures 41 and a center aperture 42receiving a pair of downwardly extending outer legs 43 and a center tab44 of the tolerance compensator 40. The outer legs 43 and the center tab44 extending into the apertures 41 and 4 2 of the driver constrain thedriver to rotate therewith and with the shaft by means of the U-shapedcage 31. pensator of spring material has a pair of preformed endportions or wings 119b biasing the driver against the contact carrier20. With the above-described arrangement, variations in manufacturingtolerances are overcome by the tolerance compensator 40 with the legs 43moving slightly inwardly or outwardly of the apertures 41. As willbecome apparent from the above description, the rim of thecircumferential wall 390 of the driver engages the contact carrier andfunctions as a bearing. Although it is preferable that the face 26a ofthe peripheral shoulder 26 integral with the shaft also engages theinner wall 12b of the chamber due tothe biasing force of the compensator40, it is feasible to have the U-shaped cage 31 engage the peripherallip 11d to provide another hearing, such bearing is not desirable sincethe area of contact is less than 360 degrees. In any event, the switch10 is provided with three bearings. when the axial hearing supportingthe rotatable shaft 24 in the bushing is included. Furthermore, bycontrolling the thickness of the spring material of the tolerancecompensator and by controlling the preformed angle of the wings 40b ofthe tolerance compensator 40 engaging the driver, various rotationaltorques are obtainable.

For the purposes of limiting end thrust or inward movement of the shaft,a circumferential slot 24b provided in the shaft retains a C-ring 45 forengaging the end of the threaded bushing 15 should excessive axialpressure be applied to the shaft.

While there has been illustrated and described what is at presentconsidered to be a preferred embodiment of the present invention, itwill be appreciated that numerous changes and modifications are likelyto occur to those skilled in the art, and it is intended in the appendedclaims to cover all those changes and modifications which fall withinthe true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In a switch, the combination of a cup-shaped housing defining achamber open at one end, a contact carrier closing the open end of thechamber, a shaft rotatably mounted in the housing and having one endextending into the chamber, a plurality of circumferentially spacedstationary contacts carried by the contact carrier and extending intothe chamber, a stationary center contact carried by the contact carrier,a driver disposed in the chamber and constrained to rotate with theshaft, a tolerance compensator biasing the driver against the contactcarrier and the shaft outwardly of the housing, a movable contactorcarried by the driver for wiping engagement with the stationary centercontact and the circumferentially spaced stationary contacts uponrotation of the shaft, and indexing means for positioning the shaft in aplurality of positions.

2. In a switch, the combination of a cup-shaped housing defining achamber open at one end, a contact carrier closing the open end of thechamber, a shaft rotatably mounted in the housing and having one endextending into the chamber, a plurality of circumferentially spacedstationary contacts carried by the contact carrier and extending intothe chamber, a stationary center contact The tolerance comcarried by thecontact carrier, contactor means for wiping engagement with thestationary contacts, a detent member having a U-shaped crosssection, thebight portion of the U being secured to the one end of the shaft, acoiled helical spring trapped by the detent member, a detent sleevehaving a plurality of radially spaced indexing fingers disposed in thechamber in concentric relationship to the shaft, a pair of detent ballsengaging the ends of the spring and biased against the indexing fingers,the diameter of the detent balls being greater than the space betweenadjacent indexing fingers, a stop member mounted in the housing, and astop arm carried by the detent member engageable with the stop memberfor limiting angular rotation of the shaft.

3. In a switch, the combination of a housing having a pair of spaced endwalls defining a chamber therebetween, a shaft rotatably journaled inone of the end walls of the housing, a plurality of circumferentiallyspaced stationary contacts mounted in the other end wall of the housingand extending into the chamber, a stationary center contact mounted inthe other end Wall, a driver disposed in the chamber and rotatable withthe shaft, a spring contactor carried by the driver and constrained torotate therewith, the spring contactor comprising a torsion bar, a pairof contact arms extending from diametrically opposite ends of thetorsion bar and provided with a pair of contact buttons for wipingengagement with the stationary contacts as the shaft is rotated.

4. In a switch, the combination of a housing provided with a chamber, aplurality of stationary contacts carried by the housing and extendinginto the chamber, a shaft journaled in the housing, a rotatable drivermounted in the chamber and operably connected to the shaft, a springcontactor constrained to rotate with the driver and engageable with atleast a pair of the stationary contacts, said spring contactorcomprising a torsion bar, a pair of arms connected to diametricallyopposite ends of the torsion bar, each arm having a connecting portionand a contact carrying portion, the connecting portions extendingoutwardly from and normal to the major axis of the torsion bar, thecontact carrying portions extending toward each other in spaced parallelplanes, a contact button carried by each of the contact carryingportions for wiping engagement with the stationary contacts uponrotation of the driver, and means for incrementally rotating the driver.

5. A switch comprising a housing, a plurality of stationary contactsextending outwardly from one end of the housing, a driver mounted in thehousing, a movable spring contacto-r engageable with at least a pair ofcontacts and constrained to rotate with the driver, a shaft rotatablyjournaled in the housing and operably connected to the driver, a detentmechanism secured to the shaft, and a tolerance compensator urging thedriver into engagement with the one end of the housing and the detentmechanism toward the other end of the housing.

6. In an electric switch having a housing provided with a chamber, ashaft journaled in the housing, a plurality of circumferentially spacedstationary contacts extending outwardly from one end of the housing andextending into the chamber, and a spring contactor for wiping engagementwith the contacts, the improvement comprising a cup-shaped driverslideably mounted on the one end of the housing, a peripheral shoulderextending radially outwardly from the shaft and provided with a radialbearing surface engaging a bearing surface in the other end of thehousing normal to the longitudinal axis of the shaft. 7. The switch ofclaim 6, wherein a tolerance compensator biases the driver against theone end of the housing and the peripheral shoulder against the other endof the housing.

8. In a switch, the combination of a cup-shaped housing defining achamber open at one end, a contact carrier closing the open end of thechamber, a shaft rotatably mounted in the housing and having one endextending into the chamber, a plurality of circumferentially spacedstationary contacts carried by the contact carrier and extending intothe chamber, a stationary center contact carried bythe contact carrier,a driver disposed in the chamber and constrained to rotate with theshaft, a tolerance compensator biasing the driver against the contactcarrier and the shaft outwardly of the housing, the driver beingprovided with a plurality of apertures, a plurality of legs integralwith the compensator slideably mounted in the apertures, a movablecontactor carried by the driver for wiping engagement with thestationary center contact and the circumferentially spaced stationarycontacts upon rotation of the shaft, and indexing means for positioningthe shaft in a plurality of positions.

9. In a switch, the combination of a housing provided with a chamberopen at one end, a contact carrier closing the open end of the chamber,a shaft rotatably mounted in the housing and extending into the chamber,a plurality of stationary contacts carried by the contact carrier andextending into the chamber, contactor means for wiping engagement withthe stationary contacts, a detent member having a U-shaped crosssection, the bight portion of the U being secured to the shaft, an indexsleeve having a plurality of radially spaced fingers disposed in thechamber in concentric relationship to the shaft, detent means carried bythe detent member and biased against the fingers, an arcuate stop memberintegral with the index sleeve and a stop arm carried by the detentmember engageable with the stop member for limiting angular rotation ofthe shaft;

it In a switch, the combination of a cylindrical housing having a pairof spaced end walls defining a chamber therebetween, a shaft rotatablyjournaled in one of the end walls of the housing, a plurality ofstationary contacts mounted in the other end wall of the housing andextending into the chamber, a driver disposed in the chamber androtatable with the shaft, a means spacing the driver from the other endwall, a spring contactor carried by the driver and constrained to rotatetherewith, the spring contactor comprising a torsion bar, a pair ofcontact arms extending from diametrically opposite ends of a torsion barhaving a pair of contact buttons for wiping engagement with thestationary contacts as the shaft is rotated.

11. In a switch, the combination of a housing provided with a firstchamber and a second chamber having a cylindrical wall, a plurality ofstationary contacts mounted in the housing, a bushing having a boreextending into the second chamber, a shaft journaled in the bore, thesecond chamber having a diameter larger than the diameter of the bore, apair of spaced cylindrical members integral with the shaft and disposedin the second chamber, a sealing washer interposed between thecylindrical members and compressed between the shaft and the cylindricalwall, a rotatable driver mounted in the second chamber and operablyconnected to the shaft, a spring contactor constrained to rotate withthe driver and engageable with at least a pair of the stationarycontacts, and means for incrementally rotating the driver.

12. The switch of claim 11, wherein the spring contaca tor comprises atorsion bar, a pair of arms are connected to diametrically opposite endsof the torsion bar, each arm having a connecting portion and a contactcarrying portion, the connecting portions extending outwardly from andnormal to the major axis of the torsion bar, the contact carryingportions extending toward each other in spaced parallel planes, and acontact button is carried by each of the contact carrying portions forwiping engagement with the stationary contacts upon rotation of thedriver.

13. The switch of claim 11, wherein the driver is provided with adepending perpiheral flange for limiting the pressure of the springcontactor against the stationary contacts, the lip of the flangeslideably engaging a bearing surface of the housing.

14. The switch of claim 13, wherein means overcoming the biasing forceof the spring contactor biases the shaft outwardly and the driveragainst the bearing surface of the housing.

15. A switch comprising a housing, a plurality of sta- 'tionary contactsextending outwardly from one end of the housing, a driver mounted in thehousing, a movable spring contactor engageable with at least a pair ofcontacts and constrained to rotate with the driver, a shaft rotatablyjournaled in the housing and operably connected to the driver, a detentmechanism secured to the shaft, a tolerance compensator, the tolerancecompensator being the only driving connection between the shaft and thedriver,

a pair of preformed wings integral with the tolerance compensatorbiasing the driver toward the one end of the References Cited by theExaminer UNITED STATES PATENTS 11/1957 Lefl'. et a1. 200-11 4/1961Nabstedt 200-11 ROBERT K. SCHAEFER, Primary Examiner,

I. R. SCOTT, Assistant Examiner.

1. IN A SWITCH, THE COMBINATION OF A CUP-SHAPED HOUSING DEFINING ACHAMBER OPEN AT ONE END, A CONTACT CARRIER CLOSING THE OPEN END OF THECHAMBER, A SHAFT ROTATABLY MOUNTED IN THE HOUSING AND HAVING ONE ENDEXTENDING INTO THE CHAMBER, A PLURALITY OF CIRCUMFERENTIALLY SPACEDSTATIONARY CONTACTS CARRIED BY THE CONTACT CARRIER AND EXTENDING INTOTHE CHAMBER, A STATIONARY CENTER CONTACT CARRIED BY THE CONTRAINED TOROTATE WITH THE SHAFT, A CHAMBER AND CONSTRAINED TO ROTATE WITH THESHAFT, A TOLERANCE COMPENSATOR BIASING THE DRIVER AGAINST THE CONTACTCARRIER AND THE SHAFT OUTWARDLY OF THE HOUSING, A MOVABLE CONTACTORCARRIED BY THE DRIVER FOR WIPING ENGAGEMENT WITH THE STATIONARY CENTERCONTACT AND THE CIRCUMFERENTIALLY SPACED STATIONARY CONTACTS UPONROTATION OF THE SHAFT, AND INDEXING MEANS FOR POSITIONING THE SHAFT IN APLURALITY OF POSITIONS.